Polyamide worm gear: manufacturing and performance

Abstract

The focus of this paper is to establish a characterisation method for seven polyamide (PA) grades to determine the major material to manufacture an automotive worm gear. The composite properties were measured according to the worm gear loadings: tensile strength, Young's modulus, abrasion and impact resistance. They were also correlated to the PA moisture absorption and its glass fibre (GF) reinforcement. The data from mechanical tests were applied in the finite element analysis (FEA) using the von Mises stress criterion. Before the rig tests of the PA worm gears, the injection process was evaluated, through the capillary rheometry. A higher difficulty to process PA 6/6 30% GF was found, due to its lower apparent viscosity. In the end, the influence of moisture absorption was as decisive to the gear's material selection as the GF to the pinion. Thus, the PAs with the best performance were: PA 6 with 30% GF (gear) and with PA 60% GF (pinion).

Post-consumer polyethylene terephthalate and polyamide 66 blends and corresponding short glass fiber reinforced composites

“…It is worth mentioning that the values for the mechanical properties of the PET/PA66/SGF composites are consistent with values reported in the literature for short glass fiber 13,14 . The mechanical properties of the PET/PA66/SGF composites reported herein (Figures 6 to 10) attest to the effective reinforcement of the PET/PA66 matrices through the incorporation of glass fibers, which is in agreement with the good dispersion of the blends (Figure 4), the homogeneous distribution, high level of orientation ( Figure 3) and optimized dispersion (Figure 2) of the glass fibers within the polymeric matrices.…”

“…Likewise, polyamide 66 (PA66) has been compounded with SGFs to produce thermoplastic composites that are widely used in technical parts requiring high mechanical and thermal properties 13,14 . The aim of this study was to prepare blends of bottle-grade post-consumer PET and virgin polyamide 66 (PA66), over the complete composition range, as well as composites of these blends reinforced with 30 wt% of SGFs (PET/PA66/SGF).…”

Polymers in gearbox production

“…The basic mechanical properties of most polymers depend on ambient temperature. On the other hand, mechanical properties of metals hardly change until the recrystallization temperature exceeds 300°C [13,14].…”

“…The plastic is used in the engineering, food, mining and metallurgical industries. It can be used to obtain, for example, rollers for transport devices, spacer sleeves, chain guides, various types of wheels, and many other products [13].…”

“…During the tests of a gear system made entirely of PA6 60% GF, surface damage to the tooth occurred after 161 cycles. The second system, using PA6 30% GF, was damaged after 623 cycles in the same areas of the gears [13].…”